Illuminating system



.Oct. 6, 1936. A. DE BRUIN 2,056,647

ILLUMINATING SYSTEM Filed July 30, 1935 INVENTOR Owvbf ow W 7;/ 619M MXZORNEFT: M

Patented Oct. 6, 1936 UNITE STATES PATENT FFICE ILLUMINATIN G SYSTEM New York Application .luly 3t, 1935, Serial No. 333% lln Germany .luly 30, 1934i 1 Claim.

The present invention relates to illuminating systems comprising a plurality of gaseous electric discharge devices, each of which has an electrode which is electron emitting when heated. 5 Each lamp in such a system is usually provided with a transformer to supply the heating current for the electron emitting electrode and has a choke coil connected in series therewith to regulate the discharge current. Both the lamp and the transformer are connected to the same current source, preferably a 220 volt alternating current source. Frequently, however, the available current source in the locality in which the system is to be installed is not a 220 volt source and, in fact, the voltage of the available current source may be anywhere within a range of 200 to 260 volts. In order to meet this situation both the choke-coil and the transformer can be provided with taps whereby the current flow through the lamp and the heating current for the electron emitting electrode can be adjusted to the desired magnitude. In certain types of systems in'which the transformer and the choke coil are located in separated positions.

05 the adjustment of the taps on the choke coil and on the transformer is complicated. In highway illuminating systems, forexample, the choke coil is mounted on the lower part'of the'supporting pole for the lamp and the transformer is mounted in the lamp fixture at the top of the pole.

The object of the present invention is to providean illuminating system of the above type which is easily adapted to operate on voltages within a comparatively large range. Still further objects and advantages attaching to the device and to its use and-operation will be apparent to those skilled in the art from the following particular description. The invention attains its object by providing the choke coil with taps and by connecting the primary of the transformer to the choke coil in such manner that a part of the choke coil can be connected into the circuit of the transformer primary and the current source. The choke coil can thus also operate as an autotransformer. The voltage impressed on the transformer primary equals the voltage of the current source plus the voltage of that part of the choke coil connected into the circuit of said transformer primary. It is thus a simple matter to arrange the taps on the choke coil in such manner that substantially'the same voltage is impressed on the transformer primary and substantially the same current flows through the the taps on the choke coil.

In the drawing accompanying and forming part of this specification two embodiments of the invention are shown, in which Fig. 1 is a schematic view of one embodiment of the invention, and

Fig. 2 is a similar view of another embodiment of the invention.

Referring to Fig. l of the drawing the new and novel illuminating system comprises a gas eous electric discharge lamp of the positive column type having a U-shaped tubular container i. Said container 5 has a gaseous atmosphere therein comprising a rare gas, such as neon, a metal vapor, such as mercury or sodium vapor, or a mixture of a starting gas, such as neon,. argon, krypton, or mixtures thereof, and a vaporizable material, such as sodium, the vapor of which is light emitting during the operation of the device. Said container i has electrodes 2 and 3 sealed therein at the ends thereof. Said electrodes 2 and 3 consist of a coiled filament, such as atungsten filament, having a coating of electron emitting material, such as barium oxide, thereon. Each of said electrodes 2 and 3 is connected to the secondary coils it and 5,

respectively, of the heating=current transformer t. The primary 7] of said transformer ii is con nected directly to the electrode 3 and to the ter minal it of an alternating current source 9. Said electrode 2 is connected to the end it of. the choke-coil it which is connected in series with the gaseous electric discharge lamp. Said chokecoil it has a plurality of taps a, b, c, d, e, j and g thereon. One of said taps is connected by lead it to the terminal it of said current source 9. The transformer primary '5 is connected by lead it to one of. the taps on said choke 6011 iii. Assuming that the above described circuit is to be connected to an alternating current source 9 the'voltage of which may be anywhere within a range of 200 to 260 volts the taps are located in such manner on the choke coil l0 that the current flow through the lamp and the voltage apill rent for the electrodes 2 and 3 when this voltage 10- is impressed on the primary I thereof the connections of the leads II and I3 to the taps on the choke coil are arranged as follows. First the lead I I is connected to that tap on the choke coil I0.

tap d for example, which connects a sufficient part of the choke coil III in series with the lamp to regulate the flow of current through the lamp to that value at which said lamp is designed to operate at maximum efiiciency, hereinafter termed the normal-value. Then the lead I! is connected to the same tap d on said choke coil Ill so that no part of the choke coil III is connected inseries with the transformer primary I.

When the voltage of the current source 9 is 230 volts a smaller part of the choke coil I 0 is connected in series with the lamp and a sumcient part of said choke coil III is connected in series with the transformer primary I to regulate the current flow through the lamp to the normal value thereof and apply a voltage of 260 volts across the transformer primary I. For example,

the lead I I isconnected to the tap c and the lead I! to tap e on said choke coil III.

When desired the transformer 8 is designed to supply a heating current of the desired magnitude on a voltage in the middle of the voltage range within which the system is designed to operate. For example, when the .voltage of current source 9 is within the range of 200 to 260 volts the transformer 8 is designed to supply a heating current of the desired magnitude when 230 volts is applied across the primary 1 thereof. When current source 8 has a voltage of 230 volts the leads I I and II are connected to the same tap on said choke coil I0. When the voltage of the current source is other than 230 volts but is within the range of 200 to 260 volts the leads II and I! are connected to different taps on the choke coil I0 to connect a larger or smaller part of the choke coil II in series with the lamp and the transformer primary 1.

The embodiment of the invention illustrated in Fig. 2 of the drawing is similar in all respects to the embodiment illustrated in Fig. 1 except that in this embodiment the lead I3 is permanently connected to the end I! of the choke coil II and an auxiliary electrode I1 is mounted on the bend on the lamp container I which electrode H isconnectedto a special coil I6 on the transformer primary I. Said auxiliary electrode II facilitates the starting of the gaseouselectric discharge .be-

r tween the electrodes 2 and 3 of the lamp. When the voltage of the current source! is 260 volts and the transformer I is designed for a voltage of 260 volts impressed on the primary I the lead anywhere from 214 to 244 volts.

II is connected to the end I5 of said choke coil I0. Said choke-coil I0 is, of course, designed to regulate the discharge current in the lamp to the normal value thereof at the voltage of the current source 9, 260 volts. When the voltage of the current source 8 is 290 volts the lead II is con nected to the tap a on said choke coil 9 which cuts out of the lamp circuit a part of the choke coil 9 and connects said choke-coil part in series with the transformer primary I. The tap a on the choke coil III is at a part thereof whereby the I discharge current in the lamp is regulated to the normal value thereof when the voltage of the current source 8 is 200 volts.

It is apparent that in the embodiment of the invention-illustrated in Fig. 2 the voltage across the transformer primary is different with differimpressed on the transformer primary I- is 260 volts. When the current source 9 has a voltage of 200 volts the voltage impressed on the transformer primary Us 227 volts. When the system is designed to operate on current sources of 200 to 260 volts and the transformer is designed for 260 volts the voltage impressed on the transformer primary is anywhere from 227 to 260 volts. When the transformer is designed for 230 volts the voltage impressed on the primary thereof is The only disadvantage of this variation of voltage impressed on the primary I with current sources of different voltage is that the electrodes 2 and 3 take a longer time to attain the operating temperature thereof on a current source voltage of 200 volts thanon a current source voltage of 260 volts. This is counterbalanced however by the advantage of having but one lead II on the choke coil I 0 which is adjusted to adapt the system to different current supply voltages.

While I have shown and described and have pointed out in the annexed claim certain novel features of the invention, it will be understood that various omissions, substitutions and changes in the forms and details of the device illustrated and in its use and operation may be made by those skilled in the art without departing from the broad spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:-

An illuminating system comprising in combination, an alternating current source, a gaseous electric discharge device comprising an electrode which is electron emitting when heated, a choke coil connected in-series with said lamp and a transformer connected in parallel with said lamp across .the terminals of said current source, said choke coil having a plurality of taps along 'the length thereof, one of the current leads for 

